Apparatus for reducing ores.



H. N. TRACY. APPARATUS FOR REDUCING ORES. APPLICATION FILED MAR. l.1-941,

Patented Sept. 17, 1918.v

' 2 SHEETS-SHEETL H. N. TRACY. APPARATUS FOR ne'nucma ORES,

APPLICATWN FILED MAR. I. I9l7.

Patented Sept. 111918.

2$HEETS-SHE'EI 2.

UNITED STATES rATENT OFFICE HARMON N. TRACY, OF LOS. ANGELES,CALIFORNIA.

APPARATUS FOR REDUCING ORES.

Specification of Letters Pateab t,

Patented Sept. 17, 11918.

Continuation of application Serial No. 23,548, filed April 24, 191%.This notification filed Mai-eh 1. 1917 Serial No. 151,629. l

To all Hi/t0!!! it may oneern:

Be it. known that I. l-zlannou 1 TntmY, a. eitizenot' the l nitedState-s, residing at Los Angeles. in the county o'l. Los Angeles. Stateof California, have invented newand useful improvements in Apparatus forReducing Ores, of whiehf the following is a specification.

This invention relates to apparatus for reducing ores; and the object ofthis invention is to provide an improved apparatus of the generaleha'raeter shown in my applira tion to. N. 23.5%. tiled '.-\pril Z-l.1915. on apparatus for redueinoores, and in my up plieation S. N.141.820. filed January 1.1, 1917, on apparatus for reducing; ores: and.to provide an improved apparatus for carrying on that proeess forredueing ores explained in my applieation S. N. 136,645, liledlhseeu'lller 12-5. 1916. This application isa eontinuatirm in part of mysaid application h. X. 23.548; and whereas in my said applieutionS.141.820, 1 claim those tern tures oi my apparatus that. referpartieularly to the shape. formation. etta, of the ore reducing stack.the introduetion of reducing agent, ete. in this present appliezu t'ionl earry on and speeitieally elaim those matters that. in my formerupplienlioii S. N. 23.548 referred pa ticularly to combination of thestack \vithfthe. eooliag chamber and various other subsidiaryparts. And,further. .l herein.explaiu and elaim eertain improvementsin theapparatus over that shown in said application; S. N. 23.548. My presentinvention will be best understood from the following[detaileddeseription of my improved and preferred form of apparatus. For thispurpose reference. is had to the aeeompanying drawings, in which: ligurel is a vertical section show ing my improved apparatus; Fig. 2 is a(rose seetion taken on linen- 2 of Fig. 1; Fig. 3 i 'a vertieal sectiontaken on line 2i.--l on Fi". lpand Fitz. l is anenlarged seetion takenas indicated by line 4 on Fig: 1. l

in the drawings I have shown a relatively long and narrow vertical orestack 10. The stack is u'tade slightly larger at the hottonr .thim atthe top in order to faei'litate the free passage of ore. downwardlytherethrough wit hout ehoking. It-is one of the features of my inventionthat the ore passes through the stack 1Q under gravitational influencebeing; treated as herein provided. physically expand: and some oresbecome past tendingto elo r and choke it there are any eonstrietious inthe stack.

1 provide a means for heating the ore \vhieh' is delivered to the upperend of the stack and I. prefer to heat theore use-lose to the upper endol the stack as possible and to deliver the ore .direetly into the stackwith the least, loss of heat. Preferably, for this purpose-I provide arevolving roasting drum ll of any preferred design. the diseharee end lloi? the drum projecting into the ut per end 1t) ot' the stark. Thedrumis placed at a suitable incline so that ore fed into its upper end11" froiuthe feed spout 12 will pass dou'n vardly through the drum.

A turnaee or burner apparatus 13 supplies heat to the roasting drum.said burner apparatus preierablj being in the form shown 1 in Fig. 1.and embodying alluid buruerlt, for gas or liquids. discharging into aconieal member L" as illustrated, air being drawn into this menrberaround the flame, as indicated inthe drawings. tontrol of the burner ishad by valve 16 or any other suitable means. The fian ie irLthe conicalmember 1.5 discharges into a furnaee ehatnher 24: which 'mayliave011G101 more cross walls ol?.briek eheekerwvork; as indicated at i 35.,From this furnace ehamber 24 the flame.

discharges aeross the upper end 10 of the stack into the heatingz androasting drum 11. The air for the furnace may be drawn in through atjaeketflti surrounding the outer part of the furnace structure, the airpassing over the exterior part of the furnace and thereby beingpreliminarily heated; and the amount of air may be controlled by anysuitable means. as by a damper located at; 9.7. which is of the typefound in U. S

Patent 246.606. A draft stackis shown at 17 connecting-with the upperendof the. roasting drum" 11; The spout leadsiftimn.

any suitable bin 18 and the feed of ore is controlled by a revolvingroller 19 0 Jerated by motor 20, which motor i contro led by acontroller 21 on the switch board 22. Switch board 22 is mounted in aconvenient position on the platform 23, said platform being preferablysupported at the upper end of the stack. As hereinafter explained, theoperation of my apparatus is under control of a single man on theplatform 23.

The ends of the drum 11 preferably p'roject into the upper end 10 of thestack 10 and into the part 17" of the draft stack 17 and the drum ll-isprovided with joint closure rings 11 of any suitable heat resistantmaterial bearing against stationary flanges 29 on the parts 10 and 17,The rings 11 may be of asbestos or the like and are made to slip, moreor'less tightly, on'the drum 11. As the drum expands longitudinally withthe heat, the rings are shoved back from the ends of the drum and remainin position to bear against the flanges whenever the drum is heated toworking temperature.

The drum 11 and furnace 1.3 not only perform the function of heating theore directly prior to its delivery to the upper end 10 'of the stack 10,but also perform the function of roasting and oxidizing the ores whichmust preferably be changed to oxids before they are reduced in thereducing stack 10. However the ores are delivered to the drum 11, itwill be presumed (for the purpose of this specification) that they aredelivered to the upper end'of the reducing stack'in the form of oxidsand the oxidized ores are discharged into the upper end of the reducingstack in suitably heated condition. The temperature of the ores isgoverned by conditions hereinafter stated. But for the certain ores,where sulfur is present, I may or "may not oxidize; I may see to itthat-no excess air is present in the roasting At the lower end of thestack I provide 7 an'accumulatinf cooling chamber 30 of suit- .ablei'oapacity r holding such a quantity ofreduced'products that coolin canbe effactually carried out before the nal product is taken out toatmosphere; that IS, coolingto-a temperature belowthe point of oxidationz. The cooling chamber 30 is at least as large as, and preferablylarger than, the

stack in'horizontal section;.so that no im- 58'1" pediment is-oifered tothe hot ore passing downwardly into the cooling chamber. In fact thecoolingchamber may be described as a preferably enlarged lower extensionor continuation of the stack. After the reduced ores are cooled they maythen be removed from the cooling chamber through a constricted opening,there being, 'then no special tendency to clog or choke; I refer toarrange the cooling means as in mated 'in' the drawings comprising anumberof transverse tubes 31 and 31 rising toward the center as shown at31, or may extend straight across the chamber as shown at 31. Theinclined tubes aid in the even distribution of the material over thewhole chamber 30. I prefer to make at least the upper rows of tubes inthis shape. At one end of the tubes I may employ a blower fan 32 of anypreferred design to provide a forced draft through the tubes; and theother end of the tubes may communicate with a chamber from which a draftstack 34 arises. This draft stack extends upwardly around the centralreducing stack; the natural draft thcrethrough may be utilized withoutthe fan to draw air through the cooling tube; and the hot air passingupwardly through the draft stack aids materially in keeping the reducingstack at proper temperature and in keeping the ores at or near theiroriginal temperature as they move down the column; forming an insulationzone around the reduction stack. The ends of some of the uppermost tubes31, the ones which are at the highest temperature, may connect with adraft pipe 35 which extends upwardly and discharges into .the air jacket26 of furnace 13. The air thus delivered to the furnace v ing in thesystem and not being lost.

At the lower end of the cooling chamber 30 I place a suitable dischargeconveyer 40 operated by motor 41- controlled b suitable controller 39 onswitch board 22. apparatus is in operation the attendant on the platform23 has full control of the introduction andwithdrawal of ore to and fromthe stack 10; and by regulating the intro-- duction and withdrawal healso regulates the rain of How of ore through the stack, and thusregulates the time period for passage of ore through the stack andthrough the reduction zone; this time period being dependent upon thetime element of the reducing'action; and this time per (i also dean mypending, in any given lant, orf ridiiferent classes of ores, on t e timeele ents of heating, oxidizin and cooling. T e introduction and witdrawal are so r that, withthe pro er rate of flow, t e stack 10 is keptconstant y full of ore which moves downwardly under-the influence o'fgravitw tion at a uniform rate, movin downwardly an on downe wardly outof-the reduction zone into into.- the reduction. zone and ulated fairlyequally from all cooling chamber below, and thence out through theconveyor 40 into any suitable conveying means or storage bins or .thelike. The conveyor 40 may preferably be a belt or link chain conveyorrunning over drums 42, within an inclosing casing 43. This casing has asloping perforated upper wall 4L4 having spaced openings 45 throughwhich the cooled reduced ore passes onto the belt conveyor. It will benoted that the openings are situated at progressively greaterheightsabove the belt (in the direction of progress of the belt), so that ateach openinga certain restricted amount of material will be taken out;and thus material is removed parts of the cooling chamber. The coolingchamber has lateral sloping bottom walls, as shown at 46, sloping downto the part 44:.

The re-agcnt employed for reduction may be varied to suit particularrequirements; I have preferred to show and describe herein a means forintroducing hydro-carbon, coal or water gas or the like to the centralparts of the reduction stack 10. I may employ a holder or tank 50 intowhich the prepared gas is passed and from which the gas is taken by-asuitable con'ipressor or'blower 51 and forced through the pipe'52 to thedistribution pipes 53. ()r the gas may be supplied under proper pressureand temperature and .in suitable quantity from any convenient source;as, for instance, direct from a gas producer of any kind. I prefer toheat the reducing agent, which may be done by uti' lining heat from thefurnace (and therefore also from the cooling ores, because, as hereinexplained, heat from the cooling ores is conducted to the furnace). Thisis done by passing the gas through a coil 52 surrounding the furnacechamber 24, embedded in the furnace walls. A branch pipe 52" leads frompipe 52 to the C011 52, and flllOlThEzPlJlPfi 52 leads back to a pipe 52and is controlled byvalve 52. .A valve 58' is placed on pipe 52 betweenits points of connection with pipes 52" and 52. By proper manipulationof these valves the gas may either pass directly from pipe 52 into thedistributing pipes 54, or may pass first through coil 52, or may bedivided and pass both ways. The gaseous reagent thus is heated with heatthat would otherwise be lost by conduction and radiation. l-lcating thereducing agent obviates the necessity of heating the ore to an excessivetemperature and enables me to operate the furnace 1.5 at the temperaturerequired only to give the ore at the top of the stacka ten'iperatureapproximately, or-

ore at the point of introductipn and necessitates ori inal heating to lahigher temperature, wit consequent inefliciency. Consider:

1ng the column of' ore and material as a whole from itsupper end to itslower end at the bottom of cooling chamber 30, the pipes 53 arepreferably arranged somewhat above of gas supplied may be regulated andcontrolled by controlling the compressor driving motor 56 from thecontroller 57 on switch board 22. Proper pressure is maintained on thegas to cause its distribution through the ore in the'reducing zone atthe central portions of the stack and to cause displacement andexclusion of the atmosphere. In actual operation the pressure requiredon the reducing gas to diffuse it throughout the rcducting zone issufiicient to cause some unused gas to pass-down, along with the gaseousproducts of reduction; into the lower part of the stack and the coolingchamber. This mixture of gases is discharged along with the reduced oreat the discharge conveyer 40; and the gases are then caught in a hood 70(or are separated from the ore by any convenient means) and areconducted through a pipe 71 to thefurnace where the unused portions areburnt as fuel. It will be understood that at all points of the rohunn ofore, from top to bottom, there is a gascoi-is pressure greater thanatmospheric pressure; and this pressure effectually prevents entrance ofatmospheric air at 40. The

casing J-i surrounds the conveyor 40 and is made to form an effectivegas ight hood l3 to the upper part of which the hood 70 connccts. itwill be noted that the ore discharge opening 4.3" is well below the hood70, so

that no gas may escape; and this not only makes for efficiency but alsofor preventing the discharge of the gases around the stack where theyare dangerous to the wm'lnucn.

The size of pipe 71 is such as to carry off the gases by-the draft ofthe furnace on pipe 71 and pipe is of sufficient size. with relation tothe sizes of the pipes 31 which communicate therewith, to carry o'li'the air from those pipes.

The amount of gas to be supplied musl e suflicient to reduce the orewithin the time period taken for the ore to pass vertically through thereduction zone. The rc-.

' comes filled with zone, and the metal is thus cooled in'the' no greatvariations tion; and the operator keeps the tcmperw hire of the ore atthe most efiicicnt point, that is, at that temperature atwvhich reduction will most eiliciently take place. To enable an accurate control ofthe tempera -ture I may provide pyrometers having in- (33 on switchboard 22. The

dicators 62 and operator can accurately control the temperature so as toobtain the proper temperature at and in the reduction zone; whether thetotal reduction action, including the breaking up of the oxids and thecombination of their oxygen with the reducing agent, is exothermic orendothermic in its nature. In the one case the ore above the reductionzone is further heated by the surplus of heat arising from an exothermicaction; while in the other a surplus of heat must be supplied from thefurnace 13. The. outward spread of the reducing gas in the relativelynarrow stack, drives out and displaces atmospheric air and thus excludesfree oxygen entirely from-theclreducing zone an from the whole stack.When the apparatus is in full operation, the cooling chamber begasesfrom the reduction presence of a non-oxidizing gas.

In my process there is a continuous treatment of the ore, embodying acontinuous step of heating, roasting or oxidatiom fob owed by acontinuous step of reduction in the manner described, followed bycontinu' ous cooling. As herein explained, one of the particularfeatures of my method is the reduction step, wherein I form a constant,continuous column of preheated ore and form within that column-a zonethroughout which a reducing agent is distributed under pressuresuflicient to permeate the column and to displace and excludeatmospheric air.

It is a feature of operation that this column is not constricted at anypoint and that it gradually and uniformly expands from top to bottom. Mymethod involves the use of no excessively high temperatures, and of oftemperature. In fact, the temperatures throughout my method are veryclose to the total average, and the average temperature is fairly low.The ores are initially heated to no higher point than necessary tocompletely carry on the action of reduction; and, as hereinbeforestated, I preheat the reducing agent for this purose. Introduction ofhot gas, rather than cold, has the effect of keeping up the temperatureof the downwardly'moving ore and of keeping the ore at thereaction'temperature longer-than would otherwise be possible. I keep asmuch'heat as possible within the system of operations. .The air jacketsurrounding the stack carries heat from the cooling reduced ores to'theore column, ma-

terially preventing loss of heat from the ores assing downwardly in thecolumn. Heat is also conveyed from the cooling ores to the roastingsurface, and thus conveys. heat to the ores at the point of preheating.

Having described a preferred form of my invention, I claim:

1. Ore reducing apparatus, embodying a relative? long andnarrow-vertical stack substan ially unobstructed and free fromconstrictions from end end so that ore may move 'therethrough undergravitational action, means for heating ore at the-upper end of thestack and for introducing the heated ore to the upper end of the stack,1neans'fo r withdrawing ore from the lower end of the stack, means tointroduce afluid reducing agent tothe stack and ore col umn near itscentral portion, means at the lower end of the stack to cool the ore,and means for transferring heat from the cooling ore to the ore beingheated.

2. Ore reducing apparatus, embodying a. relatively long and narrowvertical stack substantially unobstructed and free from constrictionsfrom end to end so that ore may move therethrough under gravitationalaction, means for heating ore at the upper end of the stack and forintroducing the heated ore to the upper end of the stack, means forwithdrawing ore from the lower end of the stack, means to-introduce afluid reducing agent to the stack and ore col-' umn near its centralportion, said stack having at its lower end a cooli g chamber of largersize than the .tack and the stack discharging into the cooling chamberwithout constriction.

3. Ore reducing apparatus, embodying a, relatively long and narrowvertical stack through which ore may gravitate, fuel'burn ing furnacemeans for heating the ore and delivering it into the upper end of thestack, means for withdrawing ore from the lower endof the stack, meansto introduce a fluid reducing agent to the stack and ore column near itscentral portion, means at the oint of withdrawal of the ore to carry offt e gases withdrawn with the ore, and means to direct said gases-intothe ore heatin furnace. 4

Ore reducing apparatus, embodying'a relatively long and narrow vertical"stack through which ore may ravitate, means forheating the ore and deivering' it into upper end of the stack,..means for withdrawing orestack, means to introduce a fluid reducing agent to the stack andore-columntherein cooling means for the ore at the lower end 0 thestack, and means to direct heat from the cooling ore to the ore-columnin the stack.

5. The herein described method of reduc; ing ores, embodying firstcontinuously heating the. ore, then continuously introducing theheatedore'intea vertical column of heatfrom the lower end of the ed oreof substantially uniform diameter from top to bottom and free fromconstrim tions, continuously introducin a reducing agent near thecentral part of t e column of ore and continuouslywithdrawi reduced oreat the bottom of the column, t e. rate of introduction and withdrawal ofthe ore being such as to keep the column of ore constant, continuouslycooling the ore at the" bottom of the column, and transferring heat fromthe cooling ore to the ore being heated.

6. The herein described method of reducing ores, embodying firstcontinuously heating the me, then continuously introducing the heatedore into a vertical column of heated ore of substantially uniformdiameter from top to bottom and free from concoolin ore.

7. T he herein described method of reducing ores, embodyingfirstroasting the ore and heating it to a temperature approximately that ofthe reduction of its metal, then subjecting the ore to the action of areducing agent, then cooling the ore, and in- "continuously;

sulatin the ore being reduced by a jacket of flui carrylng heat from thecooling ore.

8. The herein described method of treatingores, embodying firstcontinuously heat- .ing the ore, then continuously introducingthe'heated-ore into a vertical column of heated ore, continuouslyintroducing a reducing agent near file central art of the column,Withdrawmg reduced ore at the bottom of the column, and withdrawinggases at the bottom of the column and burn- In'g those gasesto initiallyheat the ore.

9. The herein described method of reducing ores, embodying firstcontinuously heating the ore to a temperature approximately that of thereduction action of its metal,"

then continuously gravitating the ore througlra vertical column of orehaving no constrictions from top to bottom, continu ously introducing afluid reducing agent at ordinary temperatures to the central part of theore column under pressure to displace and exclude atmosphere, andcontinuously withdrawing reduced ore from the lower end of the'column,the introduction and Withdrawal of ore being regulated so as to keep thecolumn constant.

. r In witness that I claimthe foregoing I have hereunto subscribed myname this 21st day of February, 1917.

HARMON N. TRACY.

Witnesses:

Enwoon H. BARKELEW, VIRGINIA Bnnmonn.

001110: of thin patent my be obtained for in cents each, by addressingthe commissioner of Intent, Washington, 10,0.

